1. Field of the Invention
This invention relates generally to safety alarms and the like, and is more particularly concerned with a method and apparatus for providing a reliable reset means for a personal alert safety system as long as the user is conscious.
2. Discussion Of The Prior Art
Firefighters, and others in hazardous locations, wear a personal alert safety system, or PASS. The PASS is designed to alert others in the event a person loses consciousness. In the demanding circumstances of a fire scene, for example, a firefighter could lose consciousness and no one may notice. The PASS, then, is designed to emit a signal that can be heard by close-by buddies in the event a firefighter loses consciousness.
The conventional PASS utilizes a motion sensor to determine whether or not the wearer is conscious, so the device must be moved periodically to indicate that the wearer is conscious. It will be understood, however, that a firefighter may need to be rather still at times, even though he is actively fighting a fire. As a result, the conventional PASS often indicates that the person is unconscious when he is not.
The PASS is designed to emit a pre-alert signal when the PASS has been motionless for a predetermined length of time. The wearer, if conscious, can then move, or hit the PASS device, and the device will reset. However, the requirement to take active steps to re-set the PASS takes time and attention away from the job at hand. Furthermore, other people in the vicinity may also hear the pre-alert signal and move in order to reset their own PASS, either mistaking the pre-alert signal for theirs, or simply being reminded that they must move occasionally.
There are times when the wearer of a PASS does not hear the pre-alert signal, and the PASS emits the full alarm signal, which is loud enough that others in the vicinity will hear the alarm. First, this requires that the wearer of the PASS use his hand in order to reset the PASS and stop the alarm from sounding. Next, others in the vicinity will stop what they are doing and go to the rescue of the person whose alarm sounded. As a result, several people are taken away from their duties, even though no one is in trouble.
In view of the above mentioned difficulties, firefighters frequently do not turn on their PASS. While this prevents false alarms, it also takes away the proposed benefit of the PASS. Thus, the prior art has not provided means for accurately determining when the wearer of a PASS device has lost consciousness so the PASS alert signal can be sounded appropriately.